1. Field of the Invention
The present invention relates to a method of fabricating a semiconductor device such as a semiconductor LSI etc., particularly to the fabrication of a laminated wiring structure on the semiconductor device which is composed of an aluminum or aluminum alloy layer and a high melting point conductive layer.
2. Description of the Related Art
A single layer wiring structure formed of an Al, Al-Si alloy, Al-Si-CU alloy, etc. layer has been employed as a wiring for a semiconductor integrated circuit device.
In order to realize the production of a highly integrated semiconductor integrated circuit device, however, a laminated structure formed of an Al or Al alloy layer and a high melting point conductive layer (e.g., TiN, TiW, WNW, WSi.sub.2 etc.) has recently been employed as a wiring layer. This is because the breakage of wire is liable to occur in the single layer wiring structure formed of an Al or Al alloy layer alone, due to stress-migration or electromigration during heat treatment as the wiring layer employs finer wiring and thinner films. A laminated wiring structure composed of an Al or Al alloy layer and a high melting point conductive layer can prevent failure of the whole semiconductor integrated circuit device, even if the Al or Al alloy layer is broken, since the high melting point conductive layer maintains its electric conductivity. However, if the Al or Al alloy wirings are broken at random positions, irregular variations between the wiring resistance components occur which affect the operating speed and operational timing of the internal circuits. As a result, the overall characteristics of the semiconductor integrated circuit device are deteriorated.